The best I've found for FMQ using the 30 wt and thicker threads are Superior Titanium Topstich needles in the 100/16 size. They seem to last forever and cure many tension issues.
I also use Superior Titanium Topstitch needles in my Juki TL98Q (older model than yours but basically the same machine). I LOVE those needles and use various sizes for every kind of thread, cotton, poly, rayon, silk, metallic, and they work GREAT. I get them at my LQS, but you can also order them directly from Superior Threads online.